The saXholder PRO is very comfortable and takes the weight of the saxophone away from my shoulders. It feels almost like the instrument is floating, and it makes longer playing sessions much easier on the body. Another plus is that it folds up small enough to fit in my sax bag, so it is convenient to carry around.
The only downside for me is when playing seated. It does not feel as natural or comfortable in that position compared to standing.
Overall, an excellent choice if you play mostly standing and want to reduce strain compared to a traditional neck strap.